1. Field of the Invention
The present invention relates to lubricant compositions useful for preventing seizing of threaded fasteners, and to a method of making same.
2. Description of the Related Art
In the use of threaded mechanical fasteners, it has been common practice to utilize anti-seizing compositions. Such compositions are applied to the threading of matable mechanical fasteners, e.g., bolt and nut elements, prior to threadably engaging the respective fastener components with one another and tightening same to their final interlocked state.
In such usage, the applied anti-seizing composition functions to maintain a lubricious medium between the mated and interlocked mechanical fastener elements, to facilitate subsequent disengagement of the fastener elements for disassembly, repair and/or reconstruction of the structural assembly comprising the mechanical fastener. Additionally, the anti-seizing composition may contain corrosion inhibitors, in addition to serving as a barrier coating on the threading which serves to minimize the oxidation thereof when the fastener is constructed of an oxidizable metal.
The prior art anti-seizing compositions have typically been formulated by dispersing metal flake in an oil-and/or-grease base composition, optionally including lubricants such as graphite powder.
Such prior art anti-seizing compositions are widely utilized and highly efficacious in minimizing seizure of mechanical fasteners for extended periods of time.
In the formulation of such anti-seizing compositions, the metal flake component, typically aluminum, is manufactured by melting of bulk aluminum ingots to form a source liquid metal. This source liquid metal then is sprayed into a cool fluid medium such as air, water, nitrogen, etc., to precipitate small particles of the metal, having generally spherical shape and diameters on the order of about 0.5-5 millimeters.
These metal particles then are introduced to a steel ball mill or other grinding system, in which the metal particles are compressed and fractured into microscopic flakes.
The microscopic flakes are formulated into the anti-seizing composition by dispersing the flakes into a vehicle or carrier medium which may for example comprise hydrotreated naphthenic oil and other hydrocarbon components, as well as fatty oils, esters, acids, suspending agents, etc. The metal flake concentration in such composition may be 80%+ by weight, based on the total weight of the anti-seizing composition.
Alternatively, the metal flake initially may be dispersed into a relatively light oil such as mineral seal oil, at a concentration of for example 60%-70% metal flake by weight, based on the total weight of the anti-seizing composition, following which the metal flake-in-oil material may be further blended with fillers or other viscosity-adjusting agents, to provide a final product composition with the appropriate application characteristics for end use.
Regardless of the specific formulation method, the resulting product is generally paste-like or sludge-like in consistency, having sufficient viscosity and sag-resistance to permit ready application to threading of matable mechanical fasteners, without subsequent dripping, sagging, or displacement from the threading locus, prior to mating and threadably locking engagement of the mechanical fastener components.
As another general consideration pertinent to the present invention and problems solved thereby, it is noted that lubricants and oils as by-products of industrial processing technologies pose significant environmental, handling and disposition issues. Specifically, hydrocarbon-based lubricants and oils as waste materials are highly regulated as to their safe disposal, and such materials have significant value as recyclable substances.
In instances where the oil medium becomes fouled or commingled with metal flash, shards, and particulates, in the course of its use, such as occurs when cutting oils are used to reduce friction and wear in machining, milling, grinding and other metal-working operations, the oil becomes disproportionately difficult and uneconomical to recycle/reprocess because of its metals content. It therefore becomes necessary to dispose of the metal-containing oil, e.g., by containment of same in leak-proof drums or containers which are subsequently stored in a long-term waste dump or other containment facility.
It therefore would be a significant advance in the field of industrial processes using oil-based lubricant media in applications involving the formation of metal-containing waste oil by-products, to provide a means and method for the cost-effective and advantageous recycling of such by-products.
It therefore is one object of the present invention to provide such means and method for the cost-effective and advantageous recycling of metal-containing waste oil by-products.
It is another object of the present invention to provide an improved method of manufacturing anti-seizing compositions, and to produce corresponding anti-seizing compositions which are equivalent or even superior to currrently and conventionally used compositions of such type.
Still other objects and advantages of the invention will be more fully apparent from the ensuing disclosure and appended claims.